About five years ago Mr Parsons discovered a sideline to the pet toy business he runs from a home workshop in Ferntree Gully. He has since sold "environment-enrichment" toys to almost every zoo in Australia and several overseas.

"I remember taking the kids to the zoo years ago and seeing a black panther lying around doing nothing," he said. "I thought, 'He needs something to do'."

In 2000, having moved on from work in the plastics, science and food industries to make dog toys, Mr Parsons was approached at a pet expo by Bev Drake, now curator of animals at Werribee Zoo.

"She and another woman from Melbourne Zoo asked what we had for seals and we gave them some floating frisbees and things we call thongs," Mr Parsons said. "A few days later she rang to say what a ball the seals were having."